Air agitation for can ice plants



Dec. 27, 1932. w, z g gR 1,892,026

AIR AGITATION FOR CAN ICE PLANTS Filed Nov. 8, 1930 WLKBm/m 3:. 2mm

Patented Dec. 27, 1932 YORK ICE MACHINERY CORPORATZOLI, 0F YORK, EEN'NSYLVAI TZA, A CQREQEATEGN OF DELAWARE AIR AGITATIQN F63 CAN Application filed November 8, 1930.

This invention relates to refrigeration, and particularly to air agitation systems for raw Water can ice plants.

The practice of agitating the Water in raW Water can ice plants by the injection of air through drop pipes, is fanihar to those skilled in the art.

The present invention is particularly adapted to the so-called low pressure systems, that is, those in which the air is discharged into the water under a pressure say between 1 and 4 pounds per square inch gage.

In such systems as heretofore used it is the common practice to deliver outside air to the drop pipes Without treating it any Way. During the summertime, when the outside atmosphere is usually Warm and humid, the dew point of atmospheric air is so high that untreated air deposits moisture in tiie feed pipes and in the drop pipes in th ice molds, with the result that after a sustained period of operation th moisture collects in such large quantities that it freezes in and obstructs said feed pipes and drop pipes because of the low temperature maintained in the freezing tank. The freezing of said moisture cuts off the flow of airfor agitating the Water in the ice molds.

On the other hand, during winter opera tion, the outside atmosphere is cold and dry, having a low dew point. lVhen such untreated air is introduced into the drop pipes it has a tendency to absorb or evaporate moisture from the water in the ice molds. The resultant temperature drop of the already cold air is suilicient to cause freezing of the Water at the outlets of the drop pipes. This cuts oil the flow of air to the ice molds.

The two conditions ment Led above have been prolific sourc of annoyance in low pressure ice-making systems heretofore used and have greatly reduced the production of clear connnercial ice.

I have found that in order to keep the air blowing in the ice molds continu .ily during the freezing period, it is neces y to control and maintain the slew o' of such between reasonable limits. lo accomplish this, I employ means for either dehumidifying or humidifying the as outside atmospheric conditions may require, and thus con- ICE PLANTS Serial No. 454,400.

trol the d w point of the air being used. Tov

the feed pipes and drop tubes in the ice molds, T

i employ means for heating the air during cold Weather so as to ofiset the cooling eflect of the cold atmosphere which then surrounds the freezing tank and also tl e cooling effect on the air pipes of the brine used for freezing the ice in the molds.

By fining the moisture content of the air as above described and in cold Weather heating such air, I am enabled to control the dew point and relative humidity of the air being used for agitating the Water in the ice molds and from this it becomes possible to prevent freezing up of the air pipes, Without introducing an undue amount of heat into the molds.

The present invention provides asystem in which the air may be dehumidified in summer, or humidified and heated in Winter. An important secondary feature is provision for the circulation of conditioned air in one or more closed circuits and in quantity far in excess of the demand for air for agitation. The circulated air thus acts to stabilize conditions in the air system and maintains the desired temperature and humidity of air to the point of use even in the most remote cans. Air for the cans is drawn from this circuit.

The air discharged into the cans is replaced by atmospheric air drawn into the air circulating system through an air Washer, the system being so contrived that pressure in the circuit is maintained constant and only so much air is drawn in from the atmosphere as is necessary for make-up purposes.

The invention is not restricted to the use of any particular type of air Washer, nor to the use of any particular type of heater, and many commercial types are known, and may be availed of.

In the accompanying drawing, however,

here is illustrated one embodiment of the invention, Which in practice, has demonstrated utility, and which is believed to offer practical operative advantages.

In the drawing Fig. l is a perspective view illustrating a can ice plant with the present invention applied.

Fig. 2 is a longitudinal axial section through the air washer.

In Fig. 1 the showing is to some extent diagrammatic, the cans being illustrated in outline and only a few of the drop pipes being shown. It will be understood, however, that each can would, in practice, he provided with a. drop pipe.

6 represents an ordinary brine tank containing brine refrigerated by any suitable means, not shown. 7 represents the ice cans which are supported in any suitable manner and which dip into the brine in the tank 6, as usual. The construction of the tank and cans, and the mode of refrigerating the brine in the tank, may follow any preferred practice, these details not being features of the present invention.

8 represents a supply header for the agitating air, and from th1s extend across the tank a plurality of parallel laterals 9, from which branch flexible hose 11, one for each can 7, the hose being connected to deliver air to the upper end of the drop pipe 12 which is supported in the removable cross bars 13. Only a few of the parts 11 12 and 13 are shown in Fig. 1, but it will be understood that each can is so equipped.

Contrary to the usual practice, the laterals 9 are not provided with dead ends at the far side of the tank from the supply manifold 8,

' but instead are connected to return manifold 14 which extends along the opposite side of the tank.- The supply manifold 8 is large enough to receive and enclose a heating element here indicated in the form of a heating pipe 15. This is connected, by pipes 16 and 17 with the top and bottom, respectively, of a hot water storage tank 18. The water in the tank 18 is heated by a heater 19, of any suitable form, connected thereto. In the example illustrated these connections comprise pipes 21 and 22 connected directly to the pipes 16 and 17, but any suitable arrangement might be used. A. manually operated valve 23 is provided to control the supply of makeup water to the heater. Steam. electric or other heaters might be substituted.

Air is delivered to the supply manifold 8 by a rotary blower 24, which may be of the Roots, or any other suitable type, and which is driven by an electric, or other motor 25. The blower draws air through a pipe 26 from the top of the shell 27 which forms a housing for the air washer. The return manifold 14 discharges through a pressure reducing valve 28 into the top of the shell 27. While I prefer a single pressure-reducing valve located as shown, any means for exerting an appropriate back pressure may be adopted.

The purpose of the pressure reducing valve is to held constant back pressure on the re- I turn manifold 14 sufficient to insure discharge of air through the drop pipes 12 into the cans,

and at the same time control the pressure in the drum 27 so that the blower 24 may function to draw in the necessary atmospheric air. Thisair is drawn in and allowed to bubble up through a body of water in the shell 27. This'water is ordinary city water, supplied through pipe 31 under the control of the float valve 32, which opens if the water level falls below the desired level. I

The same, or a slightly higher level is also fixed by an overflow pipe 33 which discharges through a U-trap 34 into a drain 35. The valve 32 will usually remain closed in summer because at that time condensation of moisture from the entering air will tend constantly to increase the quantity of water in the drum 27 At such times the level is maintained by the overflow 33. In winter when the tank furnishes some water for humidification the float valve assumes control.

Atmospheric air is drawn in through a pipe 36 and passes to a manifold 37 from which it passes through individually manually operated valves 38 into corresponding pipes 39. The valves 38 permit the use of one or more of the pipes 39, according to the conditions of operation, and adjustably throttle the inflow.

The pipes 39 pass through one head of the drum 27 and extend throughout the length of the lower portion of the drum 2?. Each is closed at its end remote from the valve 38, as indicated at 41, and is provided with small perforations, indicated at 42. These perforations are below the level of water in the drum 27, and therefore discharge the air in small bubbles so that the air rises through the water. The temperature of the water is controlled by a coil 43 of sinuous form which extends back and forth in the shell 27 below the water level in the shell.

Refrigerated brine at proper times is circulated in the coil 43. It may conveniently be drawn from the brine tank 6, and in the drawing there is illustrated a brine circulating pump 44 driven by a motor 45, and connected to draw brine from the tank 6 and dis charge it through the pipe 46 to the coil 43. Passing through. the coil 43. the brine returns to the tank 6 through pipe 47 When the plant is in operation, the motor 25 is kept in operation. The valve 28 is set to hold the necessary back pressure on the manifold 14 and laterals 9, and to reduce this pressure to a value slightly lower than atmospheric at the entrance to the washer, so that atmospheric air may enter against the resistance offered by the water in. drum 27.

It follows that air will be drawn from the top of the drum 2? by way of pipe 26 to the blower 24 and discharged into the manifold 8. The air then passes through the laterals 9 and the return manifold 14, except such air as discharges through the drop pipes 12. It

7 enter through the pipe required by the drop pipes in a pipes of can ice plants,

will be observed that the air'will maintain its condition to the point of use. If the air is properly conditioned initial y this minimizes the tendency for freeze-ups to occur. Such air as is not discharged through the drop pipes passes through the reducing valve 28 to the top of the drum 27, and thence to the suction of the blower 24:. If preferred, valve 28 may deliver directly to suction pipe 26, in which case the return air would not pass through the air space in drum 27. In neither case is the recirculated air subjected to repeated washing.

lVith a system properly adjusted, air will 36 in quantity just sutiicient to compensate for the outflow through the drop pipes. This air flows through one or more of the pipes 39 and bubbling up throu h the refri erated water k. L b b in the drum 27 changes its moisture content,

so that it leaves the water saturated substantially at the temperature of the water.

Under summer conditions motor 45 is perated at such a rate that air leaves drum 27 saturated at about 35 F. The heater coils are not in use. but the temperature of the manifold 8 and laterals 9 is such as to result in some reh ating; of the air. Under winter conditions the effort is to saturate the air at about F., which may or may not require operation of motor 45. depending on atmospheric temperature. Heater 15 operated at the minimum rate which will hold the temperature in the pipes 9 and drop pipes 12 above the dew point of the reated air.

What is claimed is 1. The method of supplying air to the drop pipes of can ice plants, which consists in circulating air in quantity eXceedin that closed path, withdrawing air from said circuit and delivering it to such drop pipes, and supplying: air of regulated moisture content to said circuit.

2. The method of supplying air to the drop pipes of can ice plants, which consists in circulatinsg air in quantity exceeding that required by the drop pipes in a closed path. supplying heat to said air, withdrawing; heated air from said circuit and delivering it to such drop pipes. and supplying air of resulated moisture content to said circuit.

3. The method of supplying air to the dr n pipes of can ice plants. which consists in c.

" culating air in quantity exceeding that required by the drop pipes in a closed circuit. supplying heat to said air in a portion of said circuit, withdrawing air from said circuit at a point beyond the point of heat supply and delivering such air to said drop pipes. and supplying to said circuit. between the point of withdrawal and the heater, air of regulated moisture content.

4. The method of supplying air to the drop which consists in circulating air in quantity exceeding that re quired by the drop pipes in a closed circuit, supplying heat to said air in a portion of said circuit, Withdrawing air from said circuit at a point beyond the point of heat supply and delivering such air to said drop pines, and humidifying atmospheric air and supplying it to said circuit, between the point of withdrawal and the heater.

5. The combination of a refrigerated brine tank; ice cansmounted therein; drop pipes in the ice cans; a supply manifold; a return manifold; a plurality of laterals connecting said manifolds and having connections with said drop pipes; air circulating means connected to deliver supply manifold; heating means for heating the air so supplied: a connection from the return manifold to the intake of said air circulating means; pressure reducing means in said connection; connection from the atmosphere to the intake of said air circulating means; and means in the last-named connection for controlling the moisture content of the entering air.

6. The combination of a refrigerated brine tank; ico cans mounted therein; drop pipes in the ice cans; a supply manifold; a return manifold; a plurality of laterals connecting said manifolds and having connections with said drop pipes; air circulating means connected to deliver air under pressure to the supply manifold; heating means for heating the air so supplied; a connection from the return manifold to the intake of said air circulating means; pressure reducing means in said connection; a connection from the at mosphere to the intake of said air circulatinn; means; and an air wash-er in the lastnamed connection.

7. The combination of a refrigerated brine tank; ice cans mounted therein; drop pipes in the ice cans; a supply manifold; a return manifold; a plurality of laterals connecting said manifolds and having connections with said drop pipes; air circulating means connected to deliver air under pressure to the supply manifold; heating means for heating the air so supplied; a connection from the return manifold to the intake of said air circulating means; pressure reducing means in said connection; a connection from the atmosphere to the intake of said air circulating means; and a refrigerated air washer in the last named connection.

8. The combination of a refrigerated brine tank; ice cans mounted therein; drop pipes in the ice cans: a supply manifold; a return manifold; a plurality of laterals connecting said manifolds and having connections with said drop pipes; air circulating means connected to deliver air under pressure to the supply manifold; heating means for heating the air so supplied; a connection from the returnmanifold to the intake of said air cirair under pressure to the 4 supply manifold; heating means associated with the supply manifold for heating the air therein; a connection from the return mamfold to the intake of said air circulating" means; pressure reducing means in said connection adapted to establish a sub-atmospheric intake pressure; a connection from the atmosphere to the intake of said air circulating means; and air drying means of the refrigerative type in the last named connection.

10. The combination of a refrigerated brine tank; ice cans mounted therein; drop pipes in the ice cans;a supply manifold; a return manifold; a plurality of laterals connecting said manifolds and having connec-. tions with said drop pipes; ir circulating means connected to deliver air under pressure to said supply manifold; heating means associated with the supply manifold for heating the air therein; a connection from tnc return manifold to the intake of said air circulating means; pressure reducing means in said connection adapted to establish a subatmospheric intake pressure; a connection from the atmosphere to the intake of said air circulating means; and an type in which air is drawn through a refrigerated water bath, interposed in the lastnamed connection.

11. The combination of a refrigerated brine tank; ice cans mounted therein; drop pipes in the ice cans; a supply manifold; a return manifold; a plurality of laterals connecting said manifolds and having connections with said drop pipes; air circulating means connected to deliver air under pressure to said supply manifold; heating means associated with the supply manifold for heating the air therein; a connection from the return manifold to the intake of said air circulating means; pressure reducing means in said connection adapted to establish a subatmospheric intake pressure; a connection from the atmosphere to the intake of said air circulating means; an air washer, of the type including a water bath through which air to be washed is passed, interposed in the last-named connection; and means for circulating brine from said brine tank in heat exchanging relation with said bath.

12. The method of conditioning air for use in the drop pipes of can ice plants which air washer,' of the consists in saturating air with moisture at. substantially 359 F. and then adding heat to said air in quantity sufiicient to neutral ize heat losses which will occur in the flow of the air from the point of saturation to the point of discharge into the can whereby the air will dischar e in a substantially saturated condition.

13. The method of conditioning atmospheric air originally at sub-freezing tem-' peraturesfor use in drop pipes of ice systems, which consists in adding to the air moisture sufficient to ensure saturation at approximately 35 F. and heating the air above 35 F.

14. The method of conditioning atmospheric air originally at sub-freezing tem-' peratures, for use in the drop pipes of ice systems, which consists in washing the air. with an excess of Water at approximately 35 F., and then raising the temperature of the air prior to delivery to the drop pipes.

15. The method of supplying air to the drop pipes of ice cans, which consists in adjusting the moisture content of such air to establish a dew point near to and not below the freezing temperature, heating the air before its flow to the drop pipes, sufliciently, and little more than sufiiciently to prevent attainment of the dew point temperature at the point of discharge from the drop pipe, and causing said air to flow to and part of it past the entrances to all the drop pipes, the volume of such flow materially exceeding the total air demand of the drop pipes, whereby the disturbing effects of'heat losses are minimized.

16. The method of supplying air to the drop pipes of icecans, which consists in adiustmg the moisture content of such air to establish a dew point near to but abovethe freezing temperature of water, and thereafter controlling the temperature of said air to the point of discharge in such manner that it is always above said dew point temperature and is substantially at saiddew, point temperature at the point of discharge.

17. The method of supplying air to the drop pipes of ice cans, which consists in adjusting the moisture content of such air to establish a dew point nearto'but definitely above 32 F. and adding heat to such air. before its flow to said drop pipes, in quantity sufiicient to neutralize the loss of heat in such flow, whereby the air will issue'from the drop pipes slightly above 82 F. and in a substantially saturated condition.

In testimony whereof I have signed my name to this specification.

WILLIAM .E. ZIEBER. 

